/*
 * Copyright 2018-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package io.lettuce.core.tracing;

import reactor.core.publisher.Mono;

/**
 * Interface to obtain a {@link TraceContext} allowing propagation of {@link Tracer.Span} {@link TraceContext}s across threads.
 *
 * @author Mark Paluch
 * @since 5.1
 */
@FunctionalInterface
public interface TraceContextProvider {

    /**
     * @return the {@link TraceContext}.
     */
    TraceContext getTraceContext();

    /**
     * @return the {@link TraceContext}.
     */
    default Mono<TraceContext> getTraceContextLater() {
        return Mono.justOrEmpty(getTraceContext());
    }

}
